【作者】 邱琪浩；

【导师】 刘文彬；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2008， 硕士

【摘要】 含芴基结构环氧树脂是一类二官能度的固体环氧树脂,由于引入刚性芴基,固化树脂具有高强、耐热、耐湿等优点,可作为纤维增强复合材料和电子封装材料的基体树脂。本论文合成了两种含芴结构环氧树脂,9,9-双(4-羟基苯基)芴二缩水甘油醚(DGEBF)和9,9-双(3-甲基-4-羟基苯基)芴二缩水甘油醚(DGEMBF),及两种芴基二胺类固化剂,9,9-双(4-氨基苯基)芴(BPF)和9,9-双(3-甲基-4-氨基苯基)芴(BMAPF),优化了合成反应条件,各产物分子结构均经傅立叶红外光谱(FTIR)、核磁共振波谱(NMR)和质谱(MS)确证。采用相转移催化法可高效合成芴基环氧树脂,环氧值最高可达理论值的95%左右;芴酮与芳香胺经亲核取代反应可用于制备芴基二胺类固化剂,优化工艺条件下,BPF与BMAPF的平均收率分别可达59.4%、69.2%,质量分数均可达99.4%。选用通用双酚A环氧树脂(E-44)和脂环族环氧树脂(TDE-85)对芴基环氧树脂进行共混改性,采用芳香胺类为固化剂,制备共混树脂体系。通过差示扫描量热分析(DSC)监测了各树脂体系的固化行为,并外推各体系的固化温度,结合凝胶曲线确定固化工艺。DSC结果表明,主链芴基及侧链甲基的引入使得树脂体系的反应活性下降,外推固化温度向高温段移动。对各树脂体系的剪切强度研究表明,DGEBF高温力学性能良好,但脆性大,通过向侧基引入甲基使得DGEBMF的室温力学性能得到改善;芴基二胺固化树脂高温力学性能优于通用芳香胺固化树脂;环氧树脂/固化剂的配比对树脂体系的性能亦有一定影响。通过动态热机械分析(DMTA)及热重分析(TG)进一步考察了共混树脂体系的热性能。结果表明,含芴结构环氧树脂的玻璃化转变温度及弹性模量普遍高于纯E-44及TDE-85环氧树脂,玻璃化转变温度一般随着芴基环氧树脂添加量的增加而相应提高,热失重实验具有相同的规律。当使用BPF为固化剂时,共混树脂体系的玻璃化转变温度最高可达260℃。对于芴基二胺固化剂,侧基甲基的引入会导致固化树脂的弹性模量、玻璃化转变温度及热分解温度的下降。吸水率实验表明,芴基二胺的耐水性优于DDS及DDM,除TDE-85树脂外,各芴基二胺固化体系的平衡吸水率均低于2.3%。通过共混芴基环氧树脂,可达到降低共混树脂吸水率的目的。憎水芴基及柔性甲基的引入均有利于降低固化树脂的吸水性。更多还原

【Abstract】 Fluorene-containing epoxy resins are widely used as resin matrices of fiber reinforced composites and electronic encapsulation materials as a kind of two-function solid epoxides, due to their advantages of high strength, good thermal stability and desirable moisture resistance.Two novel fluorene-containing epoxy resins, diglycidyl ether of 9,9-bis(4-hydroxyphenyl)-fluorene (DGEBF) and diglycidyl ether of 9,9-bis(3-methyl-4-hydroxyphenyl)-fluorene (DGEMBF), and two fluorene-based curing agents, 9,9-bis-(4-aminophenyl)-fluorene (BPF) and 9,9-bis-(3-methyl-4-aminophenyl)-fluorene (BMAPF), were prepared based on the recent literatures and the synthetic conditions such as reagent formula, catalyst dosage, reaction temperature and reaction time were optimized. The chemical structures of the obtained products were characterized by FTIR, NMR and MS. Fluorene-containing epoxy resins could be synthesized effectively by phase transfer catalysis, and the epoxy values of obtained epoxides reached up to 95% approximately of the theoretic calculated values. Fluorenyl diamines were prepared by the nucleophilic substitution of fluorenone and aromatic amines. Under optimal process, the average weight yield of BPF and BMAPF was 59.4% and 69.2% respectively, and the mass percentages of these two curatives were both up to 99.4%.The epoxy blends were prepared with fluorene-containing epoxy resins (DGEBF or DGEMBF), bisphenol A epoxide (E-44) and cycloaliphatic epoxy resin (TDE-85), and then cured with aromatic diamines such as BPF, BMAPF, diaminodiphenylsulfone (DDS) and diaminodiphenylmethane (DDM). The curing processes of the resulting epoxy systems were firstly investigated by gel curve tests to evaluate apparent curing activities of those epoxy systems, and then studied by differential scanning calorimetry (DSC) to obtain initial, peak and final extrapolated curing temperatures, and the optimal curing processes were finally concluded based on the results of the abovementioned testment. DSC results indicate that the cure activities of epoxy systems are restrained and all the extrapolated exothermic temperatures shifted to higher temperatures, due to the introduction of fluorene moieties to the chain backbone and the substitution of methyl for hydrogen atoms.Shear strength tests show that the cured fluorene-containing epoxy resins exhibit good high-temperature mechamcal performance and relatively poor ductility at room temperature, however, the shear strength could be improved by the substitution of methyl for hydrogen atoms in the side segments. Furthermore, the polymers cured with fluorenyl diamines possess better mechanical properties at elevated temperature than that of the polymers cured DDS or DDM. Moreover, the molar ratio of epoxide to curing agent also affects the mechanical performance of the epoxy thermosets, and a molar ratio of epoxide to curing agent ranged from 1:1 to 1:1.1 is acceptable.The thermal properties of epoxy blends were further evaluated by dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). DMTA results indicate that cured polymers bearing fluorene moieties display remarkably higher elastic modulus (E) and glass transition temperature (T_g) than those of neat cured E-44 and TDE-85 resins, and an elevated T_g would be obtained with the increased content of DGEBF in the epoxy blends. TGA results are in agreement with that of DMTA. T_g of blend reached up to 260℃when cured with BPF. Furthermore, for the fluorenyl diamines, a decreased T_g and E would be induced by the incorporation of methyl to the side groups.Moisture absorption tests indicate that the moisture resistance of fluorenyl diamines are better than that of DDS and DDM. The balance water uptake of epoxy/fluorenyl diamine system is less than 2.3% except that of TDE-85/fluorenyl diamine systems. The moisture absorption of cured resins could be reduced via blending DGEBF with general epoxides. It can be concluded that the water uptake of cured polymer could be restricted by the incorporation of hydrophobic fluorene rings and methyl groups.更多还原